1. Field of the Invention
The present invention relates generally to a stereopsis-based application. More particularly, the present invention is directed to an apparatus and method for detecting and tracking objects within corresponding detected roadway features utilizing a stereo vision configuration, thereby enabling and improving applications in autonomous systems for vehicular control.
2. Description of the Related Art
Developments in the field of computer vision and the availability of processors with increased processing speeds and multitasking capabilities have led to new and improved video-based technologies, but it has not been until only in the past few years that these developments have begun to appear in automotive applications, such as collision avoidance systems having adaptive control capabilities.
One such system that is increasingly becoming available in vehicular collision avoidance systems is adaptive cruise control (ACC), which has also been commonly referred to as active, automatic, autonomous and intelligent cruise control. ACC is similar to conventional cruise control systems in that they assist in maintaining a host vehicle's pre-set cruise speed. However, unlike conventional cruise control systems, ACC systems are configured to automatically adjust (e.g., by braking or increasing throttle) the pre-set speed of a vehicle in response to the detection of target vehicles that may enter into and impede the path of travel of the host vehicle, thereby automatically regulating the speed of the host vehicle absent voluntary actions by a driver.
Modern ACC systems, as well as other collision avoidance systems, have been known to employ the use of a headway sensor, a digital signal processor, longitudinal controller and other similar sensor and controller components coupled together for regulating separation distance between vehicles, vehicular speed and detection of drift or departing from a tracked lane of travel by a host vehicle. In ACC systems, for example, these sensors are typically housed in a front body portion of a host vehicle and are positioned to detect vehicles ahead of the host vehicle's line of travel. Information collected by these sensors are processed and supplied to the controller, which then regulates the corresponding host vehicle's throttle and braking units accordingly. If a lead vehicle in the same lane (i.e., the target vehicle) slows down or enters the lane of the host vehicle, the system sends a signal to the engine or braking units of the host vehicle to decelerate proportionally to sensor readings. Similarly, when the lane becomes clear, or the lead vehicle entering the lane accelerates, the system will re-accelerate the host vehicle back to the desired pre-set cruise speed.
Monocular vision, radar, monocular vision with radar, stereo vision with radar and lasers have all been used in enabling the sensory requirements of collision avoidance systems. Those commonly used in today's ACC systems, for example employ radar-based or laser-based sensors. Radar-based sensors bounce microwaves off the target vehicle, while laser-based sensors read light reflected off the body of the vehicle ahead. Radar-based sensors provide a slight advantage over laser-based systems in that they are unaffected by unfavorable weather conditions, such as dense fog, snow and rain. Radar-based sensors also perform better when used on target vehicles that are extremely dirty (which severely inhibits the ability to reflect light back to the laser-based sensor). However, a considerable disadvantage of radar-based sensors over laser-based sensors is their cost.
Accordingly, there exists a need to provide a more cost-effective and reliable means for detecting and tracking objects for use in vehicular collision avoidance systems.